The present invention relates to an improved safety grab protection device and, more particularly, a device that does not damage or cut the safety rope during braking and works in whichever direction it is attached on the rope.
There are a variety of safety clamps and connectors used in the scaffolding and other related industries. Each of these devices for one reason or another is in some way inferior to the present invention.
For example, Meyer (U.S. Pat. No. 3,179,994), Healy (U.S. Pat. No. 3,852,943) and Gibbs (U.S. Pat. No. 4,253,218) all disclose safety devices that contain a single cam braking arm. These devices work in only one direction and if attached to the safety rope in the wrong, upside-down, position the cam will not stop or protect against a fall. Dalmaso (U.S. Pat No. 4,560,029) has a double cam safety action but it suffers from the same problems as Meyer, Healy and Gibbs since it works in only one direction.
Gripping devices such as Vanderdonck (U.S. Pat. No. 1,362,905), Bear (U.S. Pat. No. 1,434,802), Endsor (U.S. Pat. No. 1,926,975), Lackner (U.S. Pat. No. 1,959,722) and Sharp (U.S. Pat. No. 4,140,207) appear to work in both directions have other serious flaws that make them potentially dangerous to the user. One significant problem that many of these devices suffer from is the fact that the brake cam is either tooth shaped or sharp edged which will damage the rope or even cut it when the brake cam is wedged against the safety line. Certain of these gripping designs are of such a configuration that they create the possibility that they may unexpectedly fall off the rope. Other cam levers are made of multiple parts including such parts as springs which can freeze during cold weather making them inoperable, and certain other devices will only work with one size of rope.
It is an object of the present invention to provide a safety grab protection device where the cam arms that come in contact with the rope will not damage the rope when the cam is wedged against the rope during braking and the device will also work no matter if it is attached in the up or down position to the safety rope.
It is a further object of the invention for the device to be attachable and detachable at any point on the life line. The invention further contemplates a safety device that will work on either 5/8 inch or 3/4 inch line.
The present invention provides a safety grab protection device operable bi-directionally for connecting a safety belt lanyard to a vertical safety rope or the like. The device comprises a clevis-like housing through which a safety rope can be reeved, a unitary brake cam for disposition between the ends of the clevis-like housing, the housing being apertured through its ends and the cam having a bore for alignment with the housing apertures, a removable pin for insertion through the apertures and the cam bore to pivotally join the cam to the housing. The cam also has arms extending to either side of the bore, normal to the axis of the bore so that arms are selectively articulable about the bore to pivot into apposition with the bight of the housing for alternative wedging of a rope against the bight and a rope engaging intaglio formation at the ends of the cam arms.
Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings.